I have a tom-tom and use a mat , sort of heavy bean bag, supplied by tom-tom but other makes are available.
1. handy for the 12v connection
2.under dash so not affected by light, but no issue in finding signal
3. easy to remove when not needed
4. no screws, stickies , velcro or tape....
5. zero interference with gears or brake.
6. no gauges or dials compromised
